The use of robots has become ubiquitous in the semiconductor industry. Such robots have the ability to process a large number of semiconductor wafers through many different processing technologies, and can perform repetitive tasks quickly and accurately. The use of robots is especially desirable in portions of semiconductor fabrication lines where human handling of semiconductor wafers is inefficient or undesirable. For example, many semiconductor fabrication processes, such as etching, deposition, and passivation, occur in reaction chambers having sealed environments. The use of robots allows these environments to be carefully maintained in order to minimize the likelihood of contamination and to optimize processing conditions.
Many of the robots currently used in the semiconductor industry utilize an end effector (also known as a blade or carrier) which is attached to one or more robotic arms. These robots are commonly used to load semiconductor wafers from a loading port into various processing ports within a multiple chamber reaction system. The robotic arms are then employed to retrieve the wafer from a particular port after the wafer has been processed. The wafer is then shuttled by the robotic arms to the next port for additional processing. When all processing within the reaction system is complete, the robotic arm returns the semiconductor wafer to the loading port, and the next wafer is placed into the system by the robotic arm for processing. Typically, a stack of several semiconductor wafers is handled in this manner during each process run.
Many modern semiconductor processes are performed at high temperatures (frequently in excess of 500° F.) using various thermal processing techniques. Such processes include, for example, silicide formation, implant anneals, oxidation, diffusion drive-in, and chemical vapor deposition (CVD) processes. Robots designed to handle semiconductor wafers in these processes must therefore be equipped with end effectors which can withstand the high temperature conditions they encounter. Since the modulus of aluminum decreases noticeably at higher temperatures, the use of aluminum end effectors under these conditions can lead to placement errors. It has therefore become common in the art to utilize quartz or ceramic end effectors in high temperature processes. Although quartz or ceramic end effectors are typically more expensive than their aluminum counterparts, their comparatively higher moduli at higher processing temperatures serve to minimize placement errors.